Should You Use Gasket Sealant? A Complete Guide to Proper Selection and Application

Gasket sealant is an important supporting material in mechanical assembly, helping improve sealing performance between two mating surfaces and preventing leakage of oil, water, compressed air, steam, or chemicals. However, not every gasket requires sealant. When used correctly, sealant can extend gasket life, reduce leakage, and minimize maintenance downtime. On the other hand, improper use may damage the gasket, clog passages, or make future disassembly difficult.

This article from PM-E.vn explains when gasket sealant should be used, common types available, and the best practices for industrial applications.

What Is Gasket Sealant?

Gasket sealant is a compound in paste or liquid form applied to the gasket surface or flange face to:

• Fill microscopic surface imperfections
• Improve sealing under high pressure
• Prevent leakage of oil, water, steam, and gas
• Enhance chemical and temperature resistance
• Extend the service life of gaskets and equipment

Sealants are commonly used in:

• Industrial piping systems
• Pumps and compressors
• Industrial valves
• Automotive engines
• HVAC systems
• Chemical, oil & gas, and food plants

Do All Gaskets Need Sealant?

1. Solid Gaskets Often Do Not Need Sealant

Many gasket types such as:

• EPDM gaskets
• NBR gaskets
• PTFE gaskets
• Cork gaskets
• Non-asbestos gaskets
• Graphite gaskets

are designed to seal effectively on their own when bolts are tightened properly. If the flange surfaces are flat, clean, and the gasket is correctly sized, additional sealant is usually unnecessary.

Using too much sealant may cause:

• Gasket distortion
• Uneven bolt load
• Excess sealant entering the pipeline
• Leakage after short service time

2. When Gasket Sealant Is Recommended

Damaged or Uneven Flange Surfaces

If the flange surface has:

• Light scratches
• Rust spots
• Pitting
• Minor unevenness

Sealant can help fill gaps and improve sealing.

Old or Repaired Equipment

Aged machinery often has worn or imperfect surfaces. Sealant helps compensate for these irregularities and reduce leakage.

Chemical / Water / Oil Exposure

Specialized sealants can resist:

• Hot oil
• Seawater
• Mild acids
• Alkalis
• Fuels

This makes them suitable for chemical plants and water treatment systems.

High Vibration Systems

Engines, pumps, compressors, and vibrating pipelines benefit from sealant for better sealing stability.

Common Types of Gasket Sealant

1. RTV Silicone Sealant

• Cures at room temperature
• Excellent heat resistance
• Flexible after curing

Applications:

• Engine covers
• Water pumps
• Gearboxes
• Engines

2. Non-Setting Sealant

• Does not fully harden
• Easy to remove during maintenance

Applications:

• Low-pressure joints
• Frequent maintenance systems

3. Anaerobic Sealant

• Cures between metal surfaces without air
• High pressure resistance

Applications:

• Metal threads
• Rigid steel flanges

4. Liquid Gasket

• Used in place of pre-cut gaskets
• Suitable for complex surfaces

Applications:

• Special machinery
• Non-standard sealing surfaces

How to Apply Gasket Sealant Properly

1. Clean the Surface Thoroughly

Remove:

• Old gasket residue
• Oil and grease
• Dirt and dust
• Rust

The surface must be clean and dry before application.

2. Apply a Thin Layer

Important rule:

Less is more.

Only a thin, even coat is needed.

3. Tighten Bolts Correctly

Use a cross-pattern tightening sequence and apply even torque.

4. Allow Proper Cure Time

Some sealants require curing before the system is put into operation.

Common Mistakes to Avoid

• Applying too much sealant
• Using the wrong temperature-rated sealant
• Using incompatible sealant for oil or chemicals
• Failing to clean surfaces
• Operating before cure time is complete
• Applying sealant unnecessarily on high-quality gaskets

Applications in Industrial Valves

At PM-E.vn, gasket sealants are commonly used for:

• Butterfly valves
• Gate valves
• Globe valves for steam service
• Stainless steel ball valves
• Check valves
• Pumps
• Steam, hot oil, and hot water pipelines

Especially in high-pressure or high-temperature systems, selecting the correct gasket + sealant + valve is essential.

Frequently Asked Questions

Can sealant replace a gasket?

In some cases, liquid gasket products can replace conventional gaskets, but high-pressure systems should still use standard gaskets.

Does more sealant provide better sealing?

No. Excess sealant often causes the opposite effect.

Is sealant difficult to remove?

Some RTV and anaerobic sealants bond strongly and require careful cleaning during maintenance.

Conclusion

Should you use gasket sealant? The answer is yes, but only in the right situations.

Use it when:

• Flange surfaces are lightly damaged
• Equipment is old
• Systems experience vibration
• Exposure to chemicals, oil, or high temperatures exists

Avoid unnecessary use when the gasket is new, properly fitted, and the flange surface is in good condition.

For long-lasting performance and leak-free operation, choose the right gasket + sealant + high-quality industrial valve.

👉 Contact PM-E.vn for professional advice on industrial valves, gaskets, and sealing solutions for your plant.